Motor-stethoscope



0. SMILEY. MOTOR STETHOSCOPE.

APPLICATION FILED MAY 24; 1919.

31,340,299. Patented May 18,1920.

M M INVENTOR 9 ATTORNEY UNITED srnrns PATENT onrion OR'VALL SMILEY, OFINDIANAPGLIS, INDIANA.

MOTOR-STETHOSCOPE.

Application filed May 24, 1919.

To alt whom it may concern:

Be it known that I, ORVALL SiriLnY, citizen of the United States ofAmerica, and a resident of Indianapolis, in the county of h-Zlarion andState of Indiana, have invented certain new and useful Improvements inMotor-Stethoscopes, of which the following is a specification.

This invention relates to improvements in stethoscopes and is especiallyintended for locating abnormal Working conditions in mechanical devices,particularly automobile engines. The object of the invention 1s toprovide a construction by means of which sounds entering the receiverwill become amplified therein so as to enable the operator todistinguish with greater certainty between the normal and abnormalnoises of machinery and to more readily locate the sources of abnormalsounds. Another object is to provide means within the receiver whichwill tend to render inaudible reactionary sounds therein.

The objects of the invention are accomplished by the constructionillustrated in the accompanying drawings in which Figure l is anelevation of a stethoscope receiver embodying the present invention, theview being partly cut away and in central section; and

Fig. 2 is a plan view of the amplifier, shown partially cut away.

Similar characters of reference indicate corresponding parts in bothviews and referring now to the same:

1 is a metallic shell of tapering form which is closed at its large endby a cap 2, the latter having tubular projections 3 extending therefromfor the attachment of flexible tubes 4 which are intended for connectionwith a head-piece (not shown) of the usual type for connection to theoperators ears. The small end of the shell is open for the reception ofsound waves, and

within the shell is arranged a.hollow wooden frustum 5, the ends 6 and 701 which constitute diaphragms that differ in the extent of theirrespective diameters. The annular tapering wall 8 of the frustum securedbe tween the heads 6 and 7 has approximately the same slant as the shell1, and is set in slightly from the perimeters of the heads so that itsexternal surface is held from contact with the internal surface of theshell, there being an annular space 9 between the wall and the shell.The wall and heads of the Specification of Letters Patent.

Patented May 18, 1920.

Serial No. 299,524.

I thereof in the immediate vicinity of the part to be examined. Thesound waves emanating from that vicinity where the receiver is thusapplied enters its open end and effects directly the primary diaphragm6, causing it to vibrate in conformity to the sound waves. The secondarydiaphragm is effect ed indirectly by the sound waves so that it iscaused to vibrate also therewith. The vibratory movements of the primarydiaphragm 6 are imparted to the secondary diaphragm 7 through the mediumof the annular wall 8, and'the secondary diaphragm is alsosympathetically effected with vibrations emanating from the primarydiaphragm through internal sound waves that set up within the frustumbecause of the vibration of the primary diaphragm. -lhrough thevibratory action of the secondary diaphragm sound waves set up withinthe cavity 10 in the large closed end of the receiver and these areobserved by the operator through the tubes in the customary manner.Because of the annular space 9 between the wall 8 and the shell, thewall actuates freely and also serves to exclude from the interior of thefrustum any reactionary sound waves that may be reflected from theinterior surface of the shell.

lVhat I claim is 1. In an appliance of the class described, a taperingshell, open at its small end for the reception of sound-waves, andclosed at its large end, there being tubular extensions for the passageof sound waves from the interior of the large end; and a hollow frustum,the heads of which are adapted to vibrate as diaphragms, the annulartapering wall of the frustum being set in slightly from the perimetersof the respective heads so that the external surface of the wall is heldfrom contact with the internal surface of the shell.

2. In a stethoscope receiver, a metallic shell of tapering form, thesmall end of which is open for the reception of sound waves; and anamplifier having two diaphraq ms spaced apart and an annular taperingwall connecting the two diaphragms, said amplifier being positionedwithin the tapering portion of the shell.

3. In a stethoscope receiver, a shell having an open end for thereception of sound waves and a sound cavity within its opposite end, aprimary diaphragm extending transversely within the shell near its openend; a secondary diaphragm of greater diameter than that of the formerdiaphragm and extending in parallel relation therewith, said diaphragmsbeing spaced apart; and means supported at its ends by the correspondingdiaphragms for imparting vibrating movement from the primary to thesecondary diaphragm.

4. In a stethoscope receiver having a shell with an opening therein forthe reception oi sound waves, two diaphragms of different diametersspaced apart and supported by the shell upon the interior thereof inparallel relation with each other; a thin annular wall supported at itsends respectively by said diaphragms, there being an annular spacebetween the exterior surface of the cavity and an opening for thereception of sound waves, a hollow wooden frustum posi tioned in thereceiver between its sound-cavity and the opening, the heads of thefrustuzn being adapted to vibrate as diaphragm. In testimony whereof Iafiix my signature in presence of two witnesses.

ORVALL SMILEY.

Vitnesses: ALICE FINNEY, LULU W. Wrsems.

